Thread: Generic programming example

I hope to be useful for everyone.

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
 
//Note : Java can't insert primitives into Tables,Lists or anything else expecting an Object
// So java provides wrapper types for this purpose (int ---> Integer).
public class GenericDemo {
 
    /** Creates a new instance of GenericDemo */
    public GenericDemo() {
    }
 
    public static void main(String args[]){
 
        /*
         *Here i'm create a arraylist hold integers only
         *Simple if you want create generic type
         *write_Container_Name <TypeName> varName = new write_Container_Name <TypeName>();
         *varName.Member Function and so on.
         */
        List<Integer> iArrayList = new ArrayList<Integer>();
        iArrayList.add(100);
        iArrayList.add(500);
        //View Container content.
        for(int i = 0 ; i < iArrayList.size();i++)
        {
            System.out.println(iArrayList.get(i));
        }
 
        /*
         *Here i'm create a Maplist hold string for every item.
         */
        Map<String,String> mplist = new HashMap<String,String>();
        mplist.put("0","Author : Mohamed Saleh");
        mplist.put("1","Subject : Demonstration about Generic Programming");
        mplist.put("2","Audience : Every Programmer what to know how Generic Programming Looks Like.");
        mplist.put("3" , "Subject : Generic Programming\nThis is (Genetics):Using DataStructure Object Depend On my Own Like (Any Object)\n");
        mplist.put("4","Sample without Generic : //Declare a ArrayList\n ArrayList al = new ArrayList();\n al.add(\"Object\");\n al.add(500);");
        mplist.put("5","Hint 01//This ArrayList al will manipulate with any object Type\nWhat if i want to manipulate with strings Only for specific purpose.\nSo i have to declate special type ArrayList for string in Same Time.");
        mplist.put("6","Sample with Generic// ArrayList<String> myStrList = new ArrayList<String>()");
        mplist.put("7","Hint 02//Then Using Current new Object Directly");
 
        for(int x = 0 ; x < mplist.size() ; x++){
              // Here i want to view data holds in MapList and there is a restriction (View By Key not Index Like Arrays or ArrayList)
              // so i did a convert or casting to content of Key to Object
              System.out.println(mplist.get((Object)Integer.toString(x)));
        }
 
        /*
         *Here i'm create a Hashtable holds doubles only
         */ 
        Hashtable<Double,Double> dblTable = new Hashtable<Double,Double>();
 
    }
}